/*
Copyright (c) 2007-2014, Troy D. Hanson   http://troydhanson.github.com/uthash/
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef UTLIST_H
#define UTLIST_H

#define UTLIST_VERSION 1.9.9

#include <assert.h>

/*
 * This file contains macros to manipulate singly and doubly-linked lists.
 *
 * 1. LL_ macros:  singly-linked lists.
 * 2. DL_ macros:  doubly-linked lists.
 * 3. CDL_ macros: circular doubly-linked lists.
 *
 * To use singly-linked lists, your structure must have a "next" pointer.
 * To use doubly-linked lists, your structure must "prev" and "next" pointers.
 * Either way, the pointer to the head of the list must be initialized to NULL.
 *
 * ----------------.EXAMPLE -------------------------
 * struct item {
 *      int id;
 *      struct item *prev, *next;
 * }
 *
 * struct item *list = NULL:
 *
 * int main() {
 *      struct item *item;
 *      ... allocate and populate item ...
 *      DL_APPEND(list, item);
 * }
 * --------------------------------------------------
 *
 * For doubly-linked lists, the append and delete macros are O(1)
 * For singly-linked lists, append and delete are O(n) but prepend is O(1)
 * The sort macro is O(n log(n)) for all types of single/double/circular lists.
 */

/* These macros use decltype or the earlier __typeof GNU extension.
   As decltype is only available in newer compilers (VS2010 or gcc 4.3+
   when compiling c++ code), this code uses whatever method is needed
   or, for VS2008 where neither is available, uses casting workarounds. */
#ifdef _MSC_VER                              /* MS compiler */
#if _MSC_VER >= 1600 && defined(__cplusplus) /* VS2010 or newer in C++ mode */
#define LDECLTYPE(x) decltype(x)
#else /* VS2008 or older (or VS2010 in C mode) */
#define NO_DECLTYPE
#define LDECLTYPE(x) char *
#endif
#elif defined(__ICCARM__)
#define NO_DECLTYPE
#define LDECLTYPE(x) char *
#else /* GNU, Sun and other compilers */
#define LDECLTYPE(x) __typeof(x)
#endif

/* for VS2008 we use some workarounds to get around the lack of decltype,
 * namely, we always reassign our tmp variable to the list head if we need
 * to dereference its prev/next pointers, and save/restore the real head.*/
#ifdef NO_DECLTYPE
#define _SV(elt, list)                                                                             \
  _tmp = (char *)(list);                                                                           \
  {                                                                                                \
    char **_alias = (char **)&(list);                                                              \
    *_alias = (elt);                                                                               \
  }
#define _NEXT(elt, list, next) ((char *)((list)->next))
#define _NEXTASGN(elt, list, to, next)                                                             \
  {                                                                                                \
    char **_alias = (char **)&((list)->next);                                                      \
    *_alias = (char *)(to);                                                                        \
  }
/* #define _PREV(elt,list,prev) ((char*)((list)->prev)) */
#define _PREVASGN(elt, list, to, prev)                                                             \
  {                                                                                                \
    char **_alias = (char **)&((list)->prev);                                                      \
    *_alias = (char *)(to);                                                                        \
  }
#define _RS(list)                                                                                  \
  {                                                                                                \
    char **_alias = (char **)&(list);                                                              \
    *_alias = _tmp;                                                                                \
  }
#define _CASTASGN(a, b)                                                                            \
  {                                                                                                \
    char **_alias = (char **)&(a);                                                                 \
    *_alias = (char *)(b);                                                                         \
  }
#else
#define _SV(elt, list)
#define _NEXT(elt, list, next) ((elt)->next)
#define _NEXTASGN(elt, list, to, next) ((elt)->next) = (to)
/* #define _PREV(elt,list,prev) ((elt)->prev) */
#define _PREVASGN(elt, list, to, prev) ((elt)->prev) = (to)
#define _RS(list)
#define _CASTASGN(a, b) (a) = (b)
#endif

/******************************************************************************
 * The sort macro is an adaptation of Simon Tatham's O(n log(n)) mergesort    *
 * Unwieldy variable names used here to avoid shadowing passed-in variables.  *
 *****************************************************************************/
#define LL_SORT(list, cmp) LL_SORT2(list, cmp, next)

#define LL_SORT2(list, cmp, next)                                                                  \
  do {                                                                                             \
    LDECLTYPE(list) _ls_p;                                                                         \
    LDECLTYPE(list) _ls_q;                                                                         \
    LDECLTYPE(list) _ls_e;                                                                         \
    LDECLTYPE(list) _ls_tail;                                                                      \
    int _ls_insize, _ls_nmerges, _ls_psize, _ls_qsize, _ls_i, _ls_looping;                         \
    if (list) {                                                                                    \
      _ls_insize = 1;                                                                              \
      _ls_looping = 1;                                                                             \
      while (_ls_looping) {                                                                        \
        _CASTASGN(_ls_p, list);                                                                    \
        list = NULL;                                                                               \
        _ls_tail = NULL;                                                                           \
        _ls_nmerges = 0;                                                                           \
        while (_ls_p) {                                                                            \
          _ls_nmerges++;                                                                           \
          _ls_q = _ls_p;                                                                           \
          _ls_psize = 0;                                                                           \
          for (_ls_i = 0; _ls_i < _ls_insize; _ls_i++) {                                           \
            _ls_psize++;                                                                           \
            _SV(_ls_q, list);                                                                      \
            _ls_q = _NEXT(_ls_q, list, next);                                                      \
            _RS(list);                                                                             \
            if (!_ls_q)                                                                            \
              break;                                                                               \
          }                                                                                        \
          _ls_qsize = _ls_insize;                                                                  \
          while (_ls_psize > 0 || (_ls_qsize > 0 && _ls_q)) {                                      \
            if (_ls_psize == 0) {                                                                  \
              _ls_e = _ls_q;                                                                       \
              _SV(_ls_q, list);                                                                    \
              _ls_q = _NEXT(_ls_q, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_qsize--;                                                                         \
            } else if (_ls_qsize == 0 || !_ls_q) {                                                 \
              _ls_e = _ls_p;                                                                       \
              _SV(_ls_p, list);                                                                    \
              _ls_p = _NEXT(_ls_p, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_psize--;                                                                         \
            } else if (cmp(_ls_p, _ls_q) <= 0) {                                                   \
              _ls_e = _ls_p;                                                                       \
              _SV(_ls_p, list);                                                                    \
              _ls_p = _NEXT(_ls_p, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_psize--;                                                                         \
            } else {                                                                               \
              _ls_e = _ls_q;                                                                       \
              _SV(_ls_q, list);                                                                    \
              _ls_q = _NEXT(_ls_q, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_qsize--;                                                                         \
            }                                                                                      \
            if (_ls_tail) {                                                                        \
              _SV(_ls_tail, list);                                                                 \
              _NEXTASGN(_ls_tail, list, _ls_e, next);                                              \
              _RS(list);                                                                           \
            } else {                                                                               \
              _CASTASGN(list, _ls_e);                                                              \
            }                                                                                      \
            _ls_tail = _ls_e;                                                                      \
          }                                                                                        \
          _ls_p = _ls_q;                                                                           \
        }                                                                                          \
        if (_ls_tail) {                                                                            \
          _SV(_ls_tail, list);                                                                     \
          _NEXTASGN(_ls_tail, list, NULL, next);                                                   \
          _RS(list);                                                                               \
        }                                                                                          \
        if (_ls_nmerges <= 1) {                                                                    \
          _ls_looping = 0;                                                                         \
        }                                                                                          \
        _ls_insize *= 2;                                                                           \
      }                                                                                            \
    }                                                                                              \
  } while (0)

#define DL_SORT(list, cmp) DL_SORT2(list, cmp, prev, next)

#define DL_SORT2(list, cmp, prev, next)                                                            \
  do {                                                                                             \
    LDECLTYPE(list) _ls_p;                                                                         \
    LDECLTYPE(list) _ls_q;                                                                         \
    LDECLTYPE(list) _ls_e;                                                                         \
    LDECLTYPE(list) _ls_tail;                                                                      \
    int _ls_insize, _ls_nmerges, _ls_psize, _ls_qsize, _ls_i, _ls_looping;                         \
    if (list) {                                                                                    \
      _ls_insize = 1;                                                                              \
      _ls_looping = 1;                                                                             \
      while (_ls_looping) {                                                                        \
        _CASTASGN(_ls_p, list);                                                                    \
        list = NULL;                                                                               \
        _ls_tail = NULL;                                                                           \
        _ls_nmerges = 0;                                                                           \
        while (_ls_p) {                                                                            \
          _ls_nmerges++;                                                                           \
          _ls_q = _ls_p;                                                                           \
          _ls_psize = 0;                                                                           \
          for (_ls_i = 0; _ls_i < _ls_insize; _ls_i++) {                                           \
            _ls_psize++;                                                                           \
            _SV(_ls_q, list);                                                                      \
            _ls_q = _NEXT(_ls_q, list, next);                                                      \
            _RS(list);                                                                             \
            if (!_ls_q)                                                                            \
              break;                                                                               \
          }                                                                                        \
          _ls_qsize = _ls_insize;                                                                  \
          while (_ls_psize > 0 || (_ls_qsize > 0 && _ls_q)) {                                      \
            if (_ls_psize == 0) {                                                                  \
              _ls_e = _ls_q;                                                                       \
              _SV(_ls_q, list);                                                                    \
              _ls_q = _NEXT(_ls_q, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_qsize--;                                                                         \
            } else if (_ls_qsize == 0 || !_ls_q) {                                                 \
              _ls_e = _ls_p;                                                                       \
              _SV(_ls_p, list);                                                                    \
              _ls_p = _NEXT(_ls_p, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_psize--;                                                                         \
            } else if (cmp(_ls_p, _ls_q) <= 0) {                                                   \
              _ls_e = _ls_p;                                                                       \
              _SV(_ls_p, list);                                                                    \
              _ls_p = _NEXT(_ls_p, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_psize--;                                                                         \
            } else {                                                                               \
              _ls_e = _ls_q;                                                                       \
              _SV(_ls_q, list);                                                                    \
              _ls_q = _NEXT(_ls_q, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_qsize--;                                                                         \
            }                                                                                      \
            if (_ls_tail) {                                                                        \
              _SV(_ls_tail, list);                                                                 \
              _NEXTASGN(_ls_tail, list, _ls_e, next);                                              \
              _RS(list);                                                                           \
            } else {                                                                               \
              _CASTASGN(list, _ls_e);                                                              \
            }                                                                                      \
            _SV(_ls_e, list);                                                                      \
            _PREVASGN(_ls_e, list, _ls_tail, prev);                                                \
            _RS(list);                                                                             \
            _ls_tail = _ls_e;                                                                      \
          }                                                                                        \
          _ls_p = _ls_q;                                                                           \
        }                                                                                          \
        _CASTASGN(list->prev, _ls_tail);                                                           \
        _SV(_ls_tail, list);                                                                       \
        _NEXTASGN(_ls_tail, list, NULL, next);                                                     \
        _RS(list);                                                                                 \
        if (_ls_nmerges <= 1) {                                                                    \
          _ls_looping = 0;                                                                         \
        }                                                                                          \
        _ls_insize *= 2;                                                                           \
      }                                                                                            \
    }                                                                                              \
  } while (0)

#define CDL_SORT(list, cmp) CDL_SORT2(list, cmp, prev, next)

#define CDL_SORT2(list, cmp, prev, next)                                                           \
  do {                                                                                             \
    LDECLTYPE(list) _ls_p;                                                                         \
    LDECLTYPE(list) _ls_q;                                                                         \
    LDECLTYPE(list) _ls_e;                                                                         \
    LDECLTYPE(list) _ls_tail;                                                                      \
    LDECLTYPE(list) _ls_oldhead;                                                                   \
    LDECLTYPE(list) _tmp;                                                                          \
    int _ls_insize, _ls_nmerges, _ls_psize, _ls_qsize, _ls_i, _ls_looping;                         \
    if (list) {                                                                                    \
      _ls_insize = 1;                                                                              \
      _ls_looping = 1;                                                                             \
      while (_ls_looping) {                                                                        \
        _CASTASGN(_ls_p, list);                                                                    \
        _CASTASGN(_ls_oldhead, list);                                                              \
        list = NULL;                                                                               \
        _ls_tail = NULL;                                                                           \
        _ls_nmerges = 0;                                                                           \
        while (_ls_p) {                                                                            \
          _ls_nmerges++;                                                                           \
          _ls_q = _ls_p;                                                                           \
          _ls_psize = 0;                                                                           \
          for (_ls_i = 0; _ls_i < _ls_insize; _ls_i++) {                                           \
            _ls_psize++;                                                                           \
            _SV(_ls_q, list);                                                                      \
            if (_NEXT(_ls_q, list, next) == _ls_oldhead) {                                         \
              _ls_q = NULL;                                                                        \
            } else {                                                                               \
              _ls_q = _NEXT(_ls_q, list, next);                                                    \
            }                                                                                      \
            _RS(list);                                                                             \
            if (!_ls_q)                                                                            \
              break;                                                                               \
          }                                                                                        \
          _ls_qsize = _ls_insize;                                                                  \
          while (_ls_psize > 0 || (_ls_qsize > 0 && _ls_q)) {                                      \
            if (_ls_psize == 0) {                                                                  \
              _ls_e = _ls_q;                                                                       \
              _SV(_ls_q, list);                                                                    \
              _ls_q = _NEXT(_ls_q, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_qsize--;                                                                         \
              if (_ls_q == _ls_oldhead) {                                                          \
                _ls_q = NULL;                                                                      \
              }                                                                                    \
            } else if (_ls_qsize == 0 || !_ls_q) {                                                 \
              _ls_e = _ls_p;                                                                       \
              _SV(_ls_p, list);                                                                    \
              _ls_p = _NEXT(_ls_p, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_psize--;                                                                         \
              if (_ls_p == _ls_oldhead) {                                                          \
                _ls_p = NULL;                                                                      \
              }                                                                                    \
            } else if (cmp(_ls_p, _ls_q) <= 0) {                                                   \
              _ls_e = _ls_p;                                                                       \
              _SV(_ls_p, list);                                                                    \
              _ls_p = _NEXT(_ls_p, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_psize--;                                                                         \
              if (_ls_p == _ls_oldhead) {                                                          \
                _ls_p = NULL;                                                                      \
              }                                                                                    \
            } else {                                                                               \
              _ls_e = _ls_q;                                                                       \
              _SV(_ls_q, list);                                                                    \
              _ls_q = _NEXT(_ls_q, list, next);                                                    \
              _RS(list);                                                                           \
              _ls_qsize--;                                                                         \
              if (_ls_q == _ls_oldhead) {                                                          \
                _ls_q = NULL;                                                                      \
              }                                                                                    \
            }                                                                                      \
            if (_ls_tail) {                                                                        \
              _SV(_ls_tail, list);                                                                 \
              _NEXTASGN(_ls_tail, list, _ls_e, next);                                              \
              _RS(list);                                                                           \
            } else {                                                                               \
              _CASTASGN(list, _ls_e);                                                              \
            }                                                                                      \
            _SV(_ls_e, list);                                                                      \
            _PREVASGN(_ls_e, list, _ls_tail, prev);                                                \
            _RS(list);                                                                             \
            _ls_tail = _ls_e;                                                                      \
          }                                                                                        \
          _ls_p = _ls_q;                                                                           \
        }                                                                                          \
        _CASTASGN(list->prev, _ls_tail);                                                           \
        _CASTASGN(_tmp, list);                                                                     \
        _SV(_ls_tail, list);                                                                       \
        _NEXTASGN(_ls_tail, list, _tmp, next);                                                     \
        _RS(list);                                                                                 \
        if (_ls_nmerges <= 1) {                                                                    \
          _ls_looping = 0;                                                                         \
        }                                                                                          \
        _ls_insize *= 2;                                                                           \
      }                                                                                            \
    }                                                                                              \
  } while (0)

/******************************************************************************
 * singly linked list macros (non-circular)                                   *
 *****************************************************************************/
#define LL_PREPEND(head, add) LL_PREPEND2(head, add, next)

#define LL_PREPEND2(head, add, next)                                                               \
  do {                                                                                             \
    (add)->next = head;                                                                            \
    head = add;                                                                                    \
  } while (0)

#define LL_CONCAT(head1, head2) LL_CONCAT2(head1, head2, next)

#define LL_CONCAT2(head1, head2, next)                                                             \
  do {                                                                                             \
    LDECLTYPE(head1) _tmp;                                                                         \
    if (head1) {                                                                                   \
      _tmp = head1;                                                                                \
      while (_tmp->next) {                                                                         \
        _tmp = _tmp->next;                                                                         \
      }                                                                                            \
      _tmp->next = (head2);                                                                        \
    } else {                                                                                       \
      (head1) = (head2);                                                                           \
    }                                                                                              \
  } while (0)

#define LL_APPEND(head, add) LL_APPEND2(head, add, next)

#define LL_APPEND2(head, add, next)                                                                \
  do {                                                                                             \
    LDECLTYPE(head) _tmp;                                                                          \
    (add)->next = NULL;                                                                            \
    if (head) {                                                                                    \
      _tmp = head;                                                                                 \
      while (_tmp->next) {                                                                         \
        _tmp = _tmp->next;                                                                         \
      }                                                                                            \
      _tmp->next = (add);                                                                          \
    } else {                                                                                       \
      (head) = (add);                                                                              \
    }                                                                                              \
  } while (0)

#define LL_DELETE(head, del) LL_DELETE2(head, del, next)

#define LL_DELETE2(head, del, next)                                                                \
  do {                                                                                             \
    LDECLTYPE(head) _tmp;                                                                          \
    if ((head) == (del)) {                                                                         \
      (head) = (head)->next;                                                                       \
    } else {                                                                                       \
      _tmp = head;                                                                                 \
      while (_tmp->next && (_tmp->next != (del))) {                                                \
        _tmp = _tmp->next;                                                                         \
      }                                                                                            \
      if (_tmp->next) {                                                                            \
        _tmp->next = ((del)->next);                                                                \
      }                                                                                            \
    }                                                                                              \
  } while (0)

/* Here are VS2008 replacements for LL_APPEND and LL_DELETE */
#define LL_APPEND_VS2008(head, add) LL_APPEND2_VS2008(head, add, next)

#define LL_APPEND2_VS2008(head, add, next)                                                         \
  do {                                                                                             \
    if (head) {                                                                                    \
      (add)->next = head; /* use add->next as a temp variable */                                   \
      while ((add)->next->next) {                                                                  \
        (add)->next = (add)->next->next;                                                           \
      }                                                                                            \
      (add)->next->next = (add);                                                                   \
    } else {                                                                                       \
      (head) = (add);                                                                              \
    }                                                                                              \
    (add)->next = NULL;                                                                            \
  } while (0)

#define LL_DELETE_VS2008(head, del) LL_DELETE2_VS2008(head, del, next)

#define LL_DELETE2_VS2008(head, del, next)                                                         \
  do {                                                                                             \
    if ((head) == (del)) {                                                                         \
      (head) = (head)->next;                                                                       \
    } else {                                                                                       \
      char *_tmp = (char *)(head);                                                                 \
      while ((head)->next && ((head)->next != (del))) {                                            \
        head = (head)->next;                                                                       \
      }                                                                                            \
      if ((head)->next) {                                                                          \
        (head)->next = ((del)->next);                                                              \
      }                                                                                            \
      {                                                                                            \
        char **_head_alias = (char **)&(head);                                                     \
        *_head_alias = _tmp;                                                                       \
      }                                                                                            \
    }                                                                                              \
  } while (0)
#ifdef NO_DECLTYPE
#undef LL_APPEND
#define LL_APPEND LL_APPEND_VS2008
#undef LL_DELETE
#define LL_DELETE LL_DELETE_VS2008
#undef LL_DELETE2
#define LL_DELETE2 LL_DELETE2_VS2008
#undef LL_APPEND2
#define LL_APPEND2 LL_APPEND2_VS2008
#undef LL_CONCAT /* no LL_CONCAT_VS2008 */
#undef DL_CONCAT /* no DL_CONCAT_VS2008 */
#endif
/* end VS2008 replacements */

#define LL_COUNT(head, el, counter) LL_COUNT2(head, el, counter, next)

#define LL_COUNT2(head, el, counter, next)                                                         \
  {                                                                                                \
    counter = 0;                                                                                   \
    LL_FOREACH2(head, el, next) { ++counter; }                                                     \
  }

#define LL_FOREACH(head, el) LL_FOREACH2(head, el, next)

#define LL_FOREACH2(head, el, next) for (el = head; el; el = (el)->next)

#define LL_FOREACH_SAFE(head, el, tmp) LL_FOREACH_SAFE2(head, el, tmp, next)

#define LL_FOREACH_SAFE2(head, el, tmp, next)                                                      \
  for ((el) = (head); (el) && (tmp = (el)->next, 1); (el) = tmp)

#define LL_SEARCH_SCALAR(head, out, field, val) LL_SEARCH_SCALAR2(head, out, field, val, next)

#define LL_SEARCH_SCALAR2(head, out, field, val, next)                                             \
  do {                                                                                             \
    LL_FOREACH2(head, out, next) {                                                                 \
      if ((out)->field == (val))                                                                   \
        break;                                                                                     \
    }                                                                                              \
  } while (0)

#define LL_SEARCH(head, out, elt, cmp) LL_SEARCH2(head, out, elt, cmp, next)

#define LL_SEARCH2(head, out, elt, cmp, next)                                                      \
  do {                                                                                             \
    LL_FOREACH2(head, out, next) {                                                                 \
      if ((cmp(out, elt)) == 0)                                                                    \
        break;                                                                                     \
    }                                                                                              \
  } while (0)

#define LL_REPLACE_ELEM(head, el, add)                                                             \
  do {                                                                                             \
    LDECLTYPE(head) _tmp;                                                                          \
    assert(head != NULL);                                                                          \
    assert(el != NULL);                                                                            \
    assert(add != NULL);                                                                           \
    (add)->next = (el)->next;                                                                      \
    if ((head) == (el)) {                                                                          \
      (head) = (add);                                                                              \
    } else {                                                                                       \
      _tmp = head;                                                                                 \
      while (_tmp->next && (_tmp->next != (el))) {                                                 \
        _tmp = _tmp->next;                                                                         \
      }                                                                                            \
      if (_tmp->next) {                                                                            \
        _tmp->next = (add);                                                                        \
      }                                                                                            \
    }                                                                                              \
  } while (0)

#define LL_PREPEND_ELEM(head, el, add)                                                             \
  do {                                                                                             \
    LDECLTYPE(head) _tmp;                                                                          \
    assert(head != NULL);                                                                          \
    assert(el != NULL);                                                                            \
    assert(add != NULL);                                                                           \
    (add)->next = (el);                                                                            \
    if ((head) == (el)) {                                                                          \
      (head) = (add);                                                                              \
    } else {                                                                                       \
      _tmp = head;                                                                                 \
      while (_tmp->next && (_tmp->next != (el))) {                                                 \
        _tmp = _tmp->next;                                                                         \
      }                                                                                            \
      if (_tmp->next) {                                                                            \
        _tmp->next = (add);                                                                        \
      }                                                                                            \
    }                                                                                              \
  } while (0)

/******************************************************************************
 * doubly linked list macros (non-circular)                                   *
 *****************************************************************************/
#define DL_PREPEND(head, add) DL_PREPEND2(head, add, prev, next)

#define DL_PREPEND2(head, add, prev, next)                                                         \
  do {                                                                                             \
    (add)->next = head;                                                                            \
    if (head) {                                                                                    \
      (add)->prev = (head)->prev;                                                                  \
      (head)->prev = (add);                                                                        \
    } else {                                                                                       \
      (add)->prev = (add);                                                                         \
    }                                                                                              \
    (head) = (add);                                                                                \
  } while (0)

#define DL_APPEND(head, add) DL_APPEND2(head, add, prev, next)

#define DL_APPEND2(head, add, prev, next)                                                          \
  do {                                                                                             \
    if (head) {                                                                                    \
      (add)->prev = (head)->prev;                                                                  \
      (head)->prev->next = (add);                                                                  \
      (head)->prev = (add);                                                                        \
      (add)->next = NULL;                                                                          \
    } else {                                                                                       \
      (head) = (add);                                                                              \
      (head)->prev = (head);                                                                       \
      (head)->next = NULL;                                                                         \
    }                                                                                              \
  } while (0)

#define DL_CONCAT(head1, head2) DL_CONCAT2(head1, head2, prev, next)

#define DL_CONCAT2(head1, head2, prev, next)                                                       \
  do {                                                                                             \
    LDECLTYPE(head1) _tmp;                                                                         \
    if (head2) {                                                                                   \
      if (head1) {                                                                                 \
        _tmp = (head2)->prev;                                                                      \
        (head2)->prev = (head1)->prev;                                                             \
        (head1)->prev->next = (head2);                                                             \
        (head1)->prev = _tmp;                                                                      \
      } else {                                                                                     \
        (head1) = (head2);                                                                         \
      }                                                                                            \
    }                                                                                              \
  } while (0)

#define DL_DELETE(head, del) DL_DELETE2(head, del, prev, next)

#define DL_DELETE2(head, del, prev, next)                                                          \
  do {                                                                                             \
    assert((del)->prev != NULL);                                                                   \
    if ((del)->prev == (del)) {                                                                    \
      (head) = NULL;                                                                               \
    } else if ((del) == (head)) {                                                                  \
      (del)->next->prev = (del)->prev;                                                             \
      (head) = (del)->next;                                                                        \
    } else {                                                                                       \
      (del)->prev->next = (del)->next;                                                             \
      if ((del)->next) {                                                                           \
        (del)->next->prev = (del)->prev;                                                           \
      } else {                                                                                     \
        (head)->prev = (del)->prev;                                                                \
      }                                                                                            \
    }                                                                                              \
  } while (0)

#define DL_COUNT(head, el, counter) DL_COUNT2(head, el, counter, next)

#define DL_COUNT2(head, el, counter, next)                                                         \
  {                                                                                                \
    counter = 0;                                                                                   \
    DL_FOREACH2(head, el, next) { ++counter; }                                                     \
  }

#define DL_FOREACH(head, el) DL_FOREACH2(head, el, next)

#define DL_FOREACH2(head, el, next) for (el = head; el; el = (el)->next)

/* this version is safe for deleting the elements during iteration */
#define DL_FOREACH_SAFE(head, el, tmp) DL_FOREACH_SAFE2(head, el, tmp, next)

#define DL_FOREACH_SAFE2(head, el, tmp, next)                                                      \
  for ((el) = (head); (el) && (tmp = (el)->next, 1); (el) = tmp)

/* these are identical to their singly-linked list counterparts */
#define DL_SEARCH_SCALAR LL_SEARCH_SCALAR
#define DL_SEARCH LL_SEARCH
#define DL_SEARCH_SCALAR2 LL_SEARCH_SCALAR2
#define DL_SEARCH2 LL_SEARCH2

#define DL_REPLACE_ELEM(head, el, add)                                                             \
  do {                                                                                             \
    assert(head != NULL);                                                                          \
    assert(el != NULL);                                                                            \
    assert(add != NULL);                                                                           \
    if ((head) == (el)) {                                                                          \
      (head) = (add);                                                                              \
      (add)->next = (el)->next;                                                                    \
      if ((el)->next == NULL) {                                                                    \
        (add)->prev = (add);                                                                       \
      } else {                                                                                     \
        (add)->prev = (el)->prev;                                                                  \
        (add)->next->prev = (add);                                                                 \
      }                                                                                            \
    } else {                                                                                       \
      (add)->next = (el)->next;                                                                    \
      (add)->prev = (el)->prev;                                                                    \
      (add)->prev->next = (add);                                                                   \
      if ((el)->next == NULL) {                                                                    \
        (head)->prev = (add);                                                                      \
      } else {                                                                                     \
        (add)->next->prev = (add);                                                                 \
      }                                                                                            \
    }                                                                                              \
  } while (0)

#define DL_PREPEND_ELEM(head, el, add)                                                             \
  do {                                                                                             \
    assert(head != NULL);                                                                          \
    assert(el != NULL);                                                                            \
    assert(add != NULL);                                                                           \
    (add)->next = (el);                                                                            \
    (add)->prev = (el)->prev;                                                                      \
    (el)->prev = (add);                                                                            \
    if ((head) == (el)) {                                                                          \
      (head) = (add);                                                                              \
    } else {                                                                                       \
      (add)->prev->next = (add);                                                                   \
    }                                                                                              \
  } while (0)

/******************************************************************************
 * circular doubly linked list macros                                         *
 *****************************************************************************/
#define CDL_PREPEND(head, add) CDL_PREPEND2(head, add, prev, next)

#define CDL_PREPEND2(head, add, prev, next)                                                        \
  do {                                                                                             \
    if (head) {                                                                                    \
      (add)->prev = (head)->prev;                                                                  \
      (add)->next = (head);                                                                        \
      (head)->prev = (add);                                                                        \
      (add)->prev->next = (add);                                                                   \
    } else {                                                                                       \
      (add)->prev = (add);                                                                         \
      (add)->next = (add);                                                                         \
    }                                                                                              \
    (head) = (add);                                                                                \
  } while (0)

#define CDL_DELETE(head, del) CDL_DELETE2(head, del, prev, next)

#define CDL_DELETE2(head, del, prev, next)                                                         \
  do {                                                                                             \
    if (((head) == (del)) && ((head)->next == (head))) {                                           \
      (head) = 0L;                                                                                 \
    } else {                                                                                       \
      (del)->next->prev = (del)->prev;                                                             \
      (del)->prev->next = (del)->next;                                                             \
      if ((del) == (head))                                                                         \
        (head) = (del)->next;                                                                      \
    }                                                                                              \
  } while (0)

#define CDL_COUNT(head, el, counter) CDL_COUNT2(head, el, counter, next)

#define CDL_COUNT2(head, el, counter, next)                                                        \
  {                                                                                                \
    counter = 0;                                                                                   \
    CDL_FOREACH2(head, el, next) { ++counter; }                                                    \
  }

#define CDL_FOREACH(head, el) CDL_FOREACH2(head, el, next)

#define CDL_FOREACH2(head, el, next)                                                               \
  for (el = head; el; el = ((el)->next == head ? 0L : (el)->next))

#define CDL_FOREACH_SAFE(head, el, tmp1, tmp2) CDL_FOREACH_SAFE2(head, el, tmp1, tmp2, prev, next)

#define CDL_FOREACH_SAFE2(head, el, tmp1, tmp2, prev, next)                                        \
  for ((el) = (head), ((tmp1) = (head) ? ((head)->prev) : NULL); (el) && ((tmp2) = (el)->next, 1); \
       ((el) = (((el) == (tmp1)) ? 0L : (tmp2))))

#define CDL_SEARCH_SCALAR(head, out, field, val) CDL_SEARCH_SCALAR2(head, out, field, val, next)

#define CDL_SEARCH_SCALAR2(head, out, field, val, next)                                            \
  do {                                                                                             \
    CDL_FOREACH2(head, out, next) {                                                                \
      if ((out)->field == (val))                                                                   \
        break;                                                                                     \
    }                                                                                              \
  } while (0)

#define CDL_SEARCH(head, out, elt, cmp) CDL_SEARCH2(head, out, elt, cmp, next)

#define CDL_SEARCH2(head, out, elt, cmp, next)                                                     \
  do {                                                                                             \
    CDL_FOREACH2(head, out, next) {                                                                \
      if ((cmp(out, elt)) == 0)                                                                    \
        break;                                                                                     \
    }                                                                                              \
  } while (0)

#define CDL_REPLACE_ELEM(head, el, add)                                                            \
  do {                                                                                             \
    assert(head != NULL);                                                                          \
    assert(el != NULL);                                                                            \
    assert(add != NULL);                                                                           \
    if ((el)->next == (el)) {                                                                      \
      (add)->next = (add);                                                                         \
      (add)->prev = (add);                                                                         \
      (head) = (add);                                                                              \
    } else {                                                                                       \
      (add)->next = (el)->next;                                                                    \
      (add)->prev = (el)->prev;                                                                    \
      (add)->next->prev = (add);                                                                   \
      (add)->prev->next = (add);                                                                   \
      if ((head) == (el)) {                                                                        \
        (head) = (add);                                                                            \
      }                                                                                            \
    }                                                                                              \
  } while (0)

#define CDL_PREPEND_ELEM(head, el, add)                                                            \
  do {                                                                                             \
    assert(head != NULL);                                                                          \
    assert(el != NULL);                                                                            \
    assert(add != NULL);                                                                           \
    (add)->next = (el);                                                                            \
    (add)->prev = (el)->prev;                                                                      \
    (el)->prev = (add);                                                                            \
    (add)->prev->next = (add);                                                                     \
    if ((head) == (el)) {                                                                          \
      (head) = (add);                                                                              \
    }                                                                                              \
  } while (0)

#endif /* UTLIST_H */
